blockstorage.h

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// Copyright (c) 2011-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_NODE_BLOCKSTORAGE_H
#define BITCOIN_NODE_BLOCKSTORAGE_H

#include <attributes.h>
#include <chain.h>
#include <dbwrapper.h>
#include <flatfile.h>
#include <kernel/blockmanager_opts.h>
#include <kernel/chainparams.h>
#include <kernel/cs_main.h>
#include <kernel/messagestartchars.h>
#include <primitives/block.h>
#include <streams.h>
#include <sync.h>
#include <uint256.h>
#include <util/fs.h>
#include <util/hasher.h>

#include <array>
#include <atomic>
#include <cstdint>
#include <functional>
#include <limits>
#include <map>
#include <memory>
#include <optional>
#include <set>
#include <span>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>

class BlockValidationState;
class CBlockUndo;
class Chainstate;
class ChainstateManager;
namespace Consensus {
struct Params;
}
namespace util {
class SignalInterrupt;
} // namespace util

namespace kernel {
class BlockTreeDB : public CDBWrapper
{
public:
    using CDBWrapper::CDBWrapper;
    bool WriteBatchSync(const std::vector<std::pair<int, const CBlockFileInfo*>>& fileInfo, int nLastFile, const std::vector<const CBlockIndex*>& blockinfo);
    bool ReadBlockFileInfo(int nFile, CBlockFileInfo& info);
    bool ReadLastBlockFile(int& nFile);
    bool WriteReindexing(bool fReindexing);
    void ReadReindexing(bool& fReindexing);
    bool WriteFlag(const std::string& name, bool fValue);
    bool ReadFlag(const std::string& name, bool& fValue);
    bool LoadBlockIndexGuts(const Consensus::Params& consensusParams, std::function<CBlockIndex*(const uint256&)> insertBlockIndex, const util::SignalInterrupt& interrupt)
        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
};
} // namespace kernel

namespace node {
using kernel::BlockTreeDB;

static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB
static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB
static const unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB

static constexpr size_t BLOCK_SERIALIZATION_HEADER_SIZE{std::tuple_size_v<MessageStartChars> + sizeof(unsigned int)};

static constexpr size_t UNDO_DATA_DISK_OVERHEAD{BLOCK_SERIALIZATION_HEADER_SIZE + uint256::size()};

// Because validation code takes pointers to the map's CBlockIndex objects, if
// we ever switch to another associative container, we need to either use a
// container that has stable addressing (true of all std associative
// containers), or make the key a `std::unique_ptr<CBlockIndex>`
using BlockMap = std::unordered_map<uint256, CBlockIndex, BlockHasher>;

struct CBlockIndexWorkComparator {
    bool operator()(const CBlockIndex* pa, const CBlockIndex* pb) const;
};

struct CBlockIndexHeightOnlyComparator {
    /* Only compares the height of two block indices, doesn't try to tie-break */
    bool operator()(const CBlockIndex* pa, const CBlockIndex* pb) const;
};

struct PruneLockInfo {
    int height_first{std::numeric_limits<int>::max()}; 
};

enum BlockfileType {
    // Values used as array indexes - do not change carelessly.
    NORMAL = 0,
    ASSUMED = 1,
    NUM_TYPES = 2,
};

std::ostream& operator<<(std::ostream& os, const BlockfileType& type);

struct BlockfileCursor {
    // The latest blockfile number.
    int file_num{0};

    // Track the height of the highest block in file_num whose undo
    // data has been written. Block data is written to block files in download
    // order, but is written to undo files in validation order, which is
    // usually in order by height. To avoid wasting disk space, undo files will
    // be trimmed whenever the corresponding block file is finalized and
    // the height of the highest block written to the block file equals the
    // height of the highest block written to the undo file. This is a
    // heuristic and can sometimes preemptively trim undo files that will write
    // more data later, and sometimes fail to trim undo files that can't have
    // more data written later.
    int undo_height{0};
};

std::ostream& operator<<(std::ostream& os, const BlockfileCursor& cursor);


class BlockManager
{
    friend Chainstate;
    friend ChainstateManager;

private:
    const CChainParams& GetParams() const { return m_opts.chainparams; }
    const Consensus::Params& GetConsensus() const { return m_opts.chainparams.GetConsensus(); }
    bool LoadBlockIndex(const std::optional<uint256>& snapshot_blockhash)
        EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    [[nodiscard]] bool FlushBlockFile(int blockfile_num, bool fFinalize, bool finalize_undo);

    [[nodiscard]] bool FlushUndoFile(int block_file, bool finalize = false);

    [[nodiscard]] FlatFilePos FindNextBlockPos(unsigned int nAddSize, unsigned int nHeight, uint64_t nTime);
    [[nodiscard]] bool FlushChainstateBlockFile(int tip_height);
    bool FindUndoPos(BlockValidationState& state, int nFile, FlatFilePos& pos, unsigned int nAddSize);

    AutoFile OpenUndoFile(const FlatFilePos& pos, bool fReadOnly = false) const;

    /* Calculate the block/rev files to delete based on height specified by user with RPC command pruneblockchain */
    void FindFilesToPruneManual(
        std::set<int>& setFilesToPrune,
        int nManualPruneHeight,
        const Chainstate& chain,
        ChainstateManager& chainman);

    void FindFilesToPrune(
        std::set<int>& setFilesToPrune,
        int last_prune,
        const Chainstate& chain,
        ChainstateManager& chainman);

    RecursiveMutex cs_LastBlockFile;
    std::vector<CBlockFileInfo> m_blockfile_info;

    std::array<std::optional<BlockfileCursor>, BlockfileType::NUM_TYPES>
        m_blockfile_cursors GUARDED_BY(cs_LastBlockFile) = {
            BlockfileCursor{},
            std::nullopt,
    };
    int MaxBlockfileNum() const EXCLUSIVE_LOCKS_REQUIRED(cs_LastBlockFile)
    {
        static const BlockfileCursor empty_cursor;
        const auto& normal = m_blockfile_cursors[BlockfileType::NORMAL].value_or(empty_cursor);
        const auto& assumed = m_blockfile_cursors[BlockfileType::ASSUMED].value_or(empty_cursor);
        return std::max(normal.file_num, assumed.file_num);
    }

    bool m_check_for_pruning = false;

    const bool m_prune_mode;

    const std::vector<std::byte> m_xor_key;

    std::set<CBlockIndex*> m_dirty_blockindex;

    std::set<int> m_dirty_fileinfo;

    std::unordered_map<std::string, PruneLockInfo> m_prune_locks GUARDED_BY(::cs_main);

    BlockfileType BlockfileTypeForHeight(int height);

    const kernel::BlockManagerOpts m_opts;

    const FlatFileSeq m_block_file_seq;
    const FlatFileSeq m_undo_file_seq;

public:
    using Options = kernel::BlockManagerOpts;

    explicit BlockManager(const util::SignalInterrupt& interrupt, Options opts);

    const util::SignalInterrupt& m_interrupt;
    std::atomic<bool> m_importing{false};

    std::atomic_bool m_blockfiles_indexed{true};

    BlockMap m_block_index GUARDED_BY(cs_main);

    std::optional<int> m_snapshot_height;

    std::vector<CBlockIndex*> GetAllBlockIndices() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    std::multimap<CBlockIndex*, CBlockIndex*> m_blocks_unlinked;

    std::unique_ptr<BlockTreeDB> m_block_tree_db GUARDED_BY(::cs_main);

    bool WriteBlockIndexDB() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
    bool LoadBlockIndexDB(const std::optional<uint256>& snapshot_blockhash)
        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    void ScanAndUnlinkAlreadyPrunedFiles() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    CBlockIndex* AddToBlockIndex(const CBlockHeader& block, CBlockIndex*& best_header) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    CBlockIndex* InsertBlockIndex(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    void PruneOneBlockFile(const int fileNumber) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    CBlockIndex* LookupBlockIndex(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    const CBlockIndex* LookupBlockIndex(const uint256& hash) const EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    CBlockFileInfo* GetBlockFileInfo(size_t n);

    bool WriteBlockUndo(const CBlockUndo& blockundo, BlockValidationState& state, CBlockIndex& block)
        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    FlatFilePos WriteBlock(const CBlock& block, int nHeight);

    void UpdateBlockInfo(const CBlock& block, unsigned int nHeight, const FlatFilePos& pos);

    [[nodiscard]] bool IsPruneMode() const { return m_prune_mode; }

    [[nodiscard]] uint64_t GetPruneTarget() const { return m_opts.prune_target; }
    static constexpr auto PRUNE_TARGET_MANUAL{std::numeric_limits<uint64_t>::max()};

    [[nodiscard]] bool LoadingBlocks() const { return m_importing || !m_blockfiles_indexed; }

    uint64_t CalculateCurrentUsage();

    const CBlockIndex* GetLastCheckpoint(const CCheckpointData& data) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    bool CheckBlockDataAvailability(const CBlockIndex& upper_block LIFETIMEBOUND, const CBlockIndex& lower_block LIFETIMEBOUND) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    const CBlockIndex* GetFirstBlock(
        const CBlockIndex& upper_block LIFETIMEBOUND,
        uint32_t status_mask,
        const CBlockIndex* lower_block = nullptr
    ) const EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    bool m_have_pruned = false;

    bool IsBlockPruned(const CBlockIndex& block) const EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    void UpdatePruneLock(const std::string& name, const PruneLockInfo& lock_info) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    AutoFile OpenBlockFile(const FlatFilePos& pos, bool fReadOnly = false) const;

    fs::path GetBlockPosFilename(const FlatFilePos& pos) const;

    void UnlinkPrunedFiles(const std::set<int>& setFilesToPrune) const;

    bool ReadBlock(CBlock& block, const FlatFilePos& pos) const;
    bool ReadBlock(CBlock& block, const CBlockIndex& index) const;
    bool ReadRawBlock(std::vector<uint8_t>& block, const FlatFilePos& pos) const;

    bool ReadBlockUndo(CBlockUndo& blockundo, const CBlockIndex& index) const;

    void CleanupBlockRevFiles() const;
};

// Calls ActivateBestChain() even if no blocks are imported.
void ImportBlocks(ChainstateManager& chainman, std::span<const fs::path> import_paths);
} // namespace node

#endif // BITCOIN_NODE_BLOCKSTORAGE_H